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+ =========================
+ BOOTING FR-V LINUX KERNEL
+ =========================
+
+======================
+PROVIDING A FILESYSTEM
+======================
+
+First of all, a root filesystem must be made available. This can be done in
+one of two ways:
+
+ (1) NFS Export
+
+ A filesystem should be constructed in a directory on an NFS server that
+ the target board can reach. This directory should then be NFS exported
+ such that the target board can read and write into it as root.
+
+ (2) Flash Filesystem (JFFS2 Recommended)
+
+ In this case, the image must be stored or built up on flash before it
+ can be used. A complete image can be built using the mkfs.jffs2 or
+ similar program and then downloaded and stored into flash by RedBoot.
+
+
+========================
+LOADING THE KERNEL IMAGE
+========================
+
+The kernel will need to be loaded into RAM by RedBoot (or by some alternative
+boot loader) before it can be run. The kernel image (arch/frv/boot/Image) may
+be loaded in one of three ways:
+
+ (1) Load from Flash
+
+ This is the simplest. RedBoot can store an image in the flash (see the
+ RedBoot documentation) and then load it back into RAM. RedBoot keeps
+ track of the load address, entry point and size, so the command to do
+ this is simply:
+
+ fis load linux
+
+ The image is then ready to be executed.
+
+ (2) Load by TFTP
+
+ The following command will download a raw binary kernel image from the
+ default server (as negotiated by BOOTP) and store it into RAM:
+
+ load -b 0x00100000 -r /tftpboot/image.bin
+
+ The image is then ready to be executed.
+
+ (3) Load by Y-Modem
+
+ The following command will download a raw binary kernel image across the
+ serial port that RedBoot is currently using:
+
+ load -m ymodem -b 0x00100000 -r zImage
+
+ The serial client (such as minicom) must then be told to transmit the
+ program by Y-Modem.
+
+ When finished, the image will then be ready to be executed.
+
+
+==================
+BOOTING THE KERNEL
+==================
+
+Boot the image with the following RedBoot command:
+
+ exec -c "<CMDLINE>" 0x00100000
+
+For example:
+
+ exec -c "console=ttySM0,115200 ip=:::::dhcp root=/dev/mtdblock2 rw"
+
+This will start the kernel running. Note that if the GDB-stub is compiled in,
+then the kernel will immediately wait for GDB to connect over serial before
+doing anything else. See the section on kernel debugging with GDB.
+
+The kernel command line <CMDLINE> tells the kernel where its console is and
+how to find its root filesystem. This is made up of the following components,
+separated by spaces:
+
+ (*) console=ttyS<x>[,<baud>[<parity>[<bits>[<flow>]]]]
+
+ This specifies that the system console should output through on-chip
+ serial port <x> (which can be "0" or "1").
+
+ <baud> is a standard baud rate between 1200 and 115200 (default 9600).
+
+ <parity> is a parity setting of "N", "O", "E", "M" or "S" for None, Odd,
+ Even, Mark or Space. "None" is the default.
+
+ <stop> is "7" or "8" for the number of bits per character. "8" is the
+ default.
+
+ <flow> is "r" to use flow control (XCTS on serial port 2 only). The
+ default is to not use flow control.
+
+ For example:
+
+ console=ttyS0,115200
+
+ To use the first on-chip serial port at baud rate 115200, no parity, 8
+ bits, and no flow control.
+
+ (*) root=/dev/<xxxx>
+
+ This specifies the device upon which the root filesystem resides. For
+ example:
+
+ /dev/nfs NFS root filesystem
+ /dev/mtdblock3 Fourth RedBoot partition on the System Flash
+
+ (*) rw
+
+ Start with the root filesystem mounted Read/Write.
+
+ The remaining components are all optional:
+
+ (*) ip=<ip>::::<host>:<iface>:<cfg>
+
+ Configure the network interface. If <cfg> is "off" then <ip> should
+ specify the IP address for the network device <iface>. <host> provide
+ the hostname for the device.
+
+ If <cfg> is "bootp" or "dhcp", then all of these parameters will be
+ discovered by consulting a BOOTP or DHCP server.
+
+ For example, the following might be used:
+
+ ip=192.168.73.12::::frv:eth0:off
+
+ This sets the IP address on the VDK motherboard RTL8029 ethernet chipset
+ (eth0) to be 192.168.73.12, and sets the board's hostname to be "frv".
+
+ (*) nfsroot=<server>:<dir>[,v<vers>]
+
+ This is mandatory if "root=/dev/nfs" is given as an option. It tells the
+ kernel the IP address of the NFS server providing its root filesystem,
+ and the pathname on that server of the filesystem.
+
+ The NFS version to use can also be specified. v2 and v3 are supported by
+ Linux.
+
+ For example:
+
+ nfsroot=192.168.73.1:/nfsroot-frv
+
+ (*) profile=1
+
+ Turns on the kernel profiler (accessible through /proc/profile).
+
+ (*) console=gdb0
+
+ This can be used as an alternative to the "console=ttyS..." listed
+ above. I tells the kernel to pass the console output to GDB if the
+ gdbstub is compiled in to the kernel.
+
+ If this is used, then the gdbstub passes the text to GDB, which then
+ simply dumps it to its standard output.
+
+ (*) mem=<xxx>M
+
+ Normally the kernel will work out how much SDRAM it has by reading the
+ SDRAM controller registers. That can be overridden with this
+ option. This allows the kernel to be told that it has <xxx> megabytes of
+ memory available.
+
+ (*) init=<prog> [<arg> [<arg> [<arg> ...]]]
+
+ This tells the kernel what program to run initially. By default this is
+ /sbin/init, but /sbin/sash or /bin/sh are common alternatives.
+
+ (*) vdc=...
+
+ This option configures the MB93493 companion chip visual display
+ driver. Please see Documentation/frv/mb93493/vdc.txt for more
+ information.